I purchased this girl as "roundtail female" from a local pet store. She was super aggressive in my sorority tank, so she got booted out to a solo tank - where she has been flourishing, and growing (to about two inches). Her ovipostor is difficult to see, not nearly as prominent as those in my smaller girls. Take a look and tell me what YOU think s/he is!

I'm not very experienced but I will say that he/she looks exactly like my baby fish that grew up to be male. I bought it as a baby at Petco and it went through a long stage of having fins that size and shape. So my guess is male. :)